Implantable medical devices provide a medical function such as electrical stimulation and/or physiological sensing. To provide the medical function, the implantable medical device includes electrical circuitry contained within a housing. In many implantable medical device designs, feedthrough conductors exit the housing and pass into a header structure mounted to the housing. The header structure includes one or more bores where electrical connectors are present and electrical signals are routed between the feedthrough conductors and the electrical connectors.
Medical leads or lead extensions have proximal ends that are positioned within corresponding bores of the header structure. The medical leads or lead extensions include proximal contacts that make electrical connection with the electrical connectors of the header structure. Conductors within an insulative lead body of the medical lead routes electrical signals between the electrical contacts and electrodes at the distal end of the lead body. The electrodes are positioned at a target site within the body by routing the lead between the implantation site of the implantable medical device and the target site. Electrical signals may then be passed between the electrical circuitry within the housing of the implantable medical device and the electrodes at the target site.
Typically, a set of pre-shaped lead frame conductors establish an interconnection of the feedthrough conductors to the electrical connectors. In some cases, individual conductors are manually routed from the feedthrough to the electrical connector by bending the conductor as may be necessary to achieve the proper route during construction of the header structure. In either case, problems may arise during manufacturing of the header structure, especially where the feedthrough conductors enter the header structure on one side while the electrical connectors are present on the opposite side, such as for a header structure that has laterally spaced bores. The relatively small size of the header structure and the components within the header structure makes successfully routing individual conductor wires without creating short circuits between adjacent conductors very difficult. Likewise, routing a lead frame conductor from one side of the header structure to another is troublesome as the lead frame has a pre-shaped configuration with bends that makes the manual routing awkward if not impossible.